Dear reader, welcome back to a new entry of the Lean Hydrogen blog. We know we haven’t written anything new for a while, but we wanted to take advantage of the launch of our new corporate image and our new website to resume the blog, which we are very excited about. If you haven’t seen them yet, visit https://leanhydrogen.whdev.es and let us know what you think.
Executive Summary
- The electrolysis of water is not hydrolysis.
- Hydrolysis is a reaction between an ion and water that produces a weak acid or base.
- The electrolysis of water is the dissociation of the water molecule by applying a direct current.
Introduction
We wanted to dedicate this entry to a conceptual error that we have detected, especially among new players in the hydrogen sector, which is the mistake of confusing the electrolysis of water with hydrolysis. No, sorry, but they are not the same. Don’t worry, it’s okay; it’s normal to make this association by common sense. Some of us also made this mistake at the beginning, but we had someone to correct and teach us. Now, we want to do the same for you.
Since we are not expert chemists, to explain this, we will use the reference book for any engineer who has studied chemistry in their first year. The famous: Petrucci, R. (10th edition). (2011). Química General. Pearson. You can review chapter 16 (acids and bases) and 20 (electrochemistry) to read them for yourselves.
Hydrolysis
Hydrolysis is a reaction that falls within acid-base reactions. A hydrolysis reaction is generally defined as a reaction between an ion and water. It is often said that the reacting ion has been hydrolyzed. For example, when NH4Cl is added to water, the pH decreases, indicating an increase in H3O+. Observing the reactions that occur:
- Cl- + H2O > no reaction
- NH4+ + H2O <> NH3 + H3O+
As you can see, the ammonium ion is hydrolyzed, while the chloride ion is not.
Hydrolysis only takes place if there is a chemical reaction that produces a weak acid or base.
Electrolysis
Electrolysis refers to the process of applying electrical energy to produce a non-spontaneous reaction. To carry it out, an electrolytic cell is used, which is essentially a cathode and an anode connected to a power supply. The inverse of this cell is called a voltaic cell, which produces a reaction spontaneously.
There are many types of electrolysis. There is the electrolysis of water, but for example, there is also the electrolysis of brine, which is the main source of chlorine and sodium derivatives. Additionally, there are other types of electrolysis, such as copper refining electrolysis, where the famous pure copper metal cathodes are obtained, or the electrolytic bath, used to protect or decorate cheap metals with more noble or resistant metals.
These electrolysis processes are very important for modern industry, which cannot be understood without them.
Conclusion
Although common sense might lead us to think that if an electrolyzer separates molecules using electricity, it makes sense to think that a hydrolyzer separates water into hydrogen and oxygen, this is not the case, as you have read. So next time, we recommend hacking your common sense and saying electrolyzers instead of hydrolyzers. We don’t want to hydrolyze water but electrolyze it.
